1. Field of The Invention
The present invention relates generally to an energy receiving arrangement which receive a microwave energy signal from an energy transmission apparatus, such as a solar energy satellite. The energy receiving arrangement may further be active to output a pilot signal in the direction of the energy transmission apparatus for further facilitating energy transmission. In particular, the invention relates to a solar energy receiving satellite which may be made lightweight, compact and simple of construction.
2. Description of The Related Art
Solar Power Satellites (SPS) have recently been proposed for collecting solar electrical energy and transmitting same to be received and utilized at remote locations. The collected energy would be transmitted via microwave to, for example, an orbital space station, factory, or a location on earth or another celestial body. For establishing such a system of energy transfer, efficient receiving and transmission apparatus are required.
One such system of solar energy collection/transmission has been described in the Jul. 14, 1992 issue of the Asahi Newspaper, morning edition 13, page 15. The disclosed arrangement describes an earth launched solar energy collection/transmission satellite. The satellite is adapted to mount a plurality of subarray assemblies to transmit solar energy in a direction from which a microwave pilot signal, aimed at the satellite from a remote energy receiving apparatus, is received.
For realizing such an energy transmission arrangement, for guiding an energy transmission wave and phase control of a generated microwave signal, a microwave pilot signal is emitted from the energy receiving apparatus and the subarrays of the energy transmission satellite are active to transmit electrical energy back in a target direction from which the pilot signal is received.
However, according to this arrangement, the energy receiving apparatus, which may be provided on a satellite, space station, or the like, comprises a flat surface on which a plurality of receiving antennas, or `rectennas` are provided. According to this, it is necessary to provide the energy receiving apparatus with means of detecting the direction of the transmission satellite and for enabling the apparatus to always assure that the rectenna elements are facing in the correct direction for receiving the microwave energy signal. Thus, a size and weight of the receiving apparatus becomes great, and, in addition, the cost and complexity of the apparatus is also increased.
Thus, is has been required to provide an energy receiving apparatus, for use with an energy transmission system, for use in space, for example, which may be made compact, lightweight, and simple in structure.